/* Copyright 2013-2015 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * 	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <dirent.h>
#include <limits.h>
#include <inttypes.h>

#include <ccan/array_size/array_size.h>

#include <mtd/mtd-abi.h>

#include <getopt.h>

#include <libflash/libflash.h>
#include <libflash/libffs.h>
#include <libflash/file.h>
#include <libflash/ecc.h>
#include <libflash/blocklevel.h>
#include <common/arch_flash.h>

#include "gard.h"

#define CLEARED_RECORD_ID 0xFFFFFFFF

#define FDT_ACTIVE_FLASH_PATH "/proc/device-tree/chosen/ibm,system-flash"
#define SYSFS_MTD_PATH "/sys/class/mtd/"
#define FLASH_GARD_PART "GUARD"

/* Full gard version number (possibly includes gitid). */
extern const char version[];

struct gard_ctx {
	bool ecc;
	uint32_t f_size;
	uint32_t f_pos;

	uint32_t gard_part_idx;
	uint32_t gard_data_pos;
	uint32_t gard_data_len;

	struct blocklevel_device *bl;
	struct ffs_handle *ffs;
};

/*
 * Return the size of a struct gard_ctx depending on if the buffer contains
 * ECC bits
 */
static inline size_t sizeof_gard(struct gard_ctx *ctx)
{
	return ctx->ecc ? ecc_buffer_size(sizeof(struct gard_record)) : sizeof(struct gard_record);
}

static void show_flash_err(int rc)
{
	switch (rc) {
		case FFS_ERR_BAD_MAGIC:
			fprintf(stderr, "libffs bad magic\n");
			break;
		case FFS_ERR_BAD_VERSION:
			fprintf(stderr, "libffs bad version\n");
			break;
		case FFS_ERR_BAD_CKSUM:
			fprintf(stderr, "libffs bad check sum\n");
			break;
		case FFS_ERR_PART_NOT_FOUND:
			fprintf(stderr, "libffs flash partition not found\n");
			break;
			/* ------- */
		case FLASH_ERR_MALLOC_FAILED:
			fprintf(stderr, "libflash malloc failed\n");
			break;
		case FLASH_ERR_CHIP_UNKNOWN:
			fprintf(stderr, "libflash unknown flash chip\n");
			break;
		case FLASH_ERR_PARM_ERROR:
			fprintf(stderr, "libflash parameter error\n");
			break;
		case FLASH_ERR_ERASE_BOUNDARY:
			fprintf(stderr, "libflash erase boundary error\n");
			break;
		case FLASH_ERR_WREN_TIMEOUT:
			fprintf(stderr, "libflash WREN timeout\n");
			break;
		case FLASH_ERR_WIP_TIMEOUT:
			fprintf(stderr, "libflash WIP timeout\n");
			break;
		case FLASH_ERR_VERIFY_FAILURE:
			fprintf(stderr, "libflash verification failure\n");
			break;
		case FLASH_ERR_4B_NOT_SUPPORTED:
			fprintf(stderr, "libflash 4byte mode not supported\n");
			break;
		case FLASH_ERR_CTRL_CONFIG_MISMATCH:
			fprintf(stderr, "libflash control config mismatch\n");
			break;
		case FLASH_ERR_CHIP_ER_NOT_SUPPORTED:
			fprintf(stderr, "libflash chip not supported\n");
			break;
		case FLASH_ERR_CTRL_CMD_UNSUPPORTED:
			fprintf(stderr, "libflash unsupported control command\n");
			break;
		case FLASH_ERR_CTRL_TIMEOUT:
			fprintf(stderr, "libflash control timeout\n");
			break;
		case FLASH_ERR_ECC_INVALID:
			fprintf(stderr, "libflash ecc invalid\n");
			break;
		default:
			fprintf(stderr, "A libflash/libffs error has occurred %d\n", rc);
	}
}

static const char *target_type_to_str(enum target_type t)
{
	switch (t) {
		case TYPE_NA:
			return "Not applicable";
		case TYPE_SYS:
			return "System";
		case TYPE_NODE:
			return "Node";
		case TYPE_DIMM:
			return "Dimm";
		case TYPE_MEMBUF:
			return "Memory Buffer";
		case TYPE_PROC:
			return "Processor";
		case TYPE_EX:
			return "EX";
		case TYPE_CORE:
			return "Core";
		case TYPE_L2:
			return "L2 cache";
		case TYPE_L3:
			return "L3 cache";
		case TYPE_L4:
			return "L4 cache";
		case TYPE_MCS:
			return "MSC";
		case TYPE_MBA:
			return "MBA";
		case TYPE_XBUS:
			return "XBUS";
		case TYPE_ABUS:
			return "ABUS";
		case TYPE_PCI:
			return "PCI";
		case TYPE_DPSS:
			return "DPSS";
		case TYPE_APSS:
			return "APSS";
		case TYPE_OCC:
			return "OCC";
		case TYPE_PSI:
			return "PSI";
		case TYPE_FSP:
			return "FSP";
		case TYPE_PNOR:
			return "PNOR";
		case TYPE_OSC:
			return "OSC";
		case TYPE_TODCLK:
			return "Time of day clock";
		case TYPE_CONTROL_NODE:
			return "Control Node";
		case TYPE_OSCREFCLK:
			return "OSC Ref Clock";
		case TYPE_OSCPCICLK:
			return "OSC PCI Clock";
		case TYPE_REFCLKENDPT:
			return "Ref Clock";
		case TYPE_PCICLKENDPT:
			return "PCI Clock";
		case TYPE_NX:
			return "NX";
		case TYPE_PORE:
			return "PORE";
		case TYPE_PCIESWITCH:
			return "PCIE Switch";
		case TYPE_CAPP:
			return "CAPP";
		case TYPE_FSI:
			return "FSI";
		case TYPE_TEST_FAIL:
			return "Test Fail";
		case TYPE_LAST_IN_RANGE:
			return "Last";
	}
	return "Unknown";
}

static const char *path_type_to_str(enum path_type t)
{
	switch (t) {
		case PATH_NA:
			return "not applicable";
		case PATH_AFFINITY:
			return "affinity";
		case PATH_PHYSICAL:
			return "physical";
		case PATH_DEVICE:
			return "device";
		case PATH_POWER:
			return "power";
	}
	return "Unknown";
}

static bool is_valid_id(uint32_t record_id)
{
	return record_id != CLEARED_RECORD_ID;
}

static int do_iterate(struct gard_ctx *ctx,
		int (*func)(struct gard_ctx *ctx, int pos,
			struct gard_record *gard, void *priv),
		void *priv)
{
	int rc = 0;
	unsigned int i;
	struct gard_record gard, null_gard;

	memset(&null_gard, UINT_MAX, sizeof(gard));
	for (i = 0; i * sizeof_gard(ctx) < ctx->gard_data_len && rc == 0; i++) {
		memset(&gard, 0, sizeof(gard));

		rc = blocklevel_read(ctx->bl, ctx->gard_data_pos +
				(i * sizeof_gard(ctx)), &gard, sizeof(gard));
		/* It isn't super clear what constitutes the end, this should do */
		if (rc || memcmp(&gard, &null_gard, sizeof(gard)) == 0)
			break;

		rc = func(ctx, i, &gard, priv);
	}

	return rc;
}

static int get_largest_pos_i(struct gard_ctx *ctx, int pos, struct gard_record *gard, void *priv)
{
	if (!priv)
		return -1;

	*(int *)priv = pos;

	return 0;
}

static int get_largest_pos(struct gard_ctx *ctx)
{
	int rc, largest = -1;

	rc = do_iterate(ctx, &get_largest_pos_i, &largest);
	if (rc)
		return -1;

	return largest;
}

static int count_valid_records_i(struct gard_ctx *ctx, int pos, struct gard_record *gard, void *priv)
{
	if (!gard || !priv)
		return -1;

	if (is_valid_id(be32toh(gard->record_id)))
		(*(int *)priv)++;

	return 0;
}

static int count_valid_records(struct gard_ctx *ctx)
{
	int rc, count = 0;

	rc = do_iterate(ctx, &count_valid_records_i, &count);
	if (rc)
		return 0;

	return count;
}

static int do_list_i(struct gard_ctx *ctx, int pos, struct gard_record *gard, void *priv)
{
	if (!gard)
		return -1;

	if (is_valid_id(be32toh(gard->record_id)))
		printf("| %08x | %08x | %-15s |\n", be32toh(gard->record_id), be32toh(gard->errlog_eid),
		       path_type_to_str(gard->target_id.type_size >> PATH_TYPE_SHIFT));

	return 0;
}

static int do_list(struct gard_ctx *ctx, int argc, char **argv)
{
	int rc;

	/* No entries */
	if (count_valid_records(ctx) == 0) {
		printf("No GARD entries to display\n");
		rc = 0;
	} else {
		printf("|    ID    |   Error  | Type            |\n");
		printf("+---------------------------------------+\n");
		rc = do_iterate(ctx, &do_list_i, NULL);
		printf("+=======================================+\n");
	}

	return rc;
}

static int do_show_i(struct gard_ctx *ctx, int pos, struct gard_record *gard, void *priv)
{
	uint32_t id;

	if (!priv || !gard)
		return -1;

	id = *(uint32_t *)priv;

	if (be32toh(gard->record_id) == id) {
		unsigned int count, i;

		printf("Record ID:    0x%08x\n", id);
		printf("========================\n");
		printf("Error ID:     0x%08x\n", be32toh(gard->errlog_eid));
		printf("Error Type:         0x%02x\n", gard->error_type);
		printf("Res Recovery:       0x%02x\n", gard->resource_recovery);
		printf("Path Type: %s\n", path_type_to_str(gard->target_id.type_size >> PATH_TYPE_SHIFT));
		count = gard->target_id.type_size & PATH_ELEMENTS_MASK;
		for (i = 0; i < count && i < MAX_PATH_ELEMENTS; i++)
			printf("%*c%s, Instance #%d\n", i + 1, '>', target_type_to_str(gard->target_id.path_elements[i].target_type),
			       gard->target_id.path_elements[i].instance);
	}

	return 0;
}

static int do_show(struct gard_ctx *ctx, int argc, char **argv)
{
	uint32_t id;
	int rc;

	if (argc != 2) {
		fprintf(stderr, "%s option requires a GARD record\n", argv[0]);
		return -1;
	}

	id = strtoul(argv[1], NULL, 16);

	rc = do_iterate(ctx, &do_show_i, &id);

	return rc;
}

static int do_clear_i(struct gard_ctx *ctx, int pos, struct gard_record *gard, void *priv)
{
	int largest, rc = 0;
	char *buf;
	struct gard_record null_gard;

	if (!gard || !ctx || !priv)
		return -1;

	/* Not this one */
	if (be32toh(gard->record_id) != *(uint32_t *)priv)
		return 0;

	memset(&null_gard, 0xFF, sizeof(null_gard));

	largest = get_largest_pos(ctx);

	printf("Clearing gard record 0x%08x...", be32toh(gard->record_id));

	if (largest < 0 || pos > largest) {
		/* Something went horribly wrong */
		fprintf(stderr, "largest index out of range %d\n", largest);
		return -1;
	}

	if (pos < largest) {
		/* We're not clearing the last record, shift all the records up */
		int buf_len = ((largest - pos) * sizeof(struct gard_record));
		int buf_pos = ctx->gard_data_pos + ((pos + 1) * sizeof_gard(ctx));
		buf = malloc(buf_len);
		if (!buf)
			return -ENOMEM;

		rc = blocklevel_read(ctx->bl, buf_pos, buf, buf_len);
		if (rc) {
			free(buf);
			fprintf(stderr, "Couldn't read from flash at 0x%08x for len 0x%08x\n", buf_pos, buf_len);
			return rc;
		}

		rc = blocklevel_smart_write(ctx->bl, buf_pos - sizeof_gard(ctx), buf, buf_len);
		free(buf);
		if (rc) {
			fprintf(stderr, "Couldn't write to flash at 0x%08x for len 0x%08x\n",
			        buf_pos - (int) sizeof_gard(ctx), buf_len);
			return rc;
		}
	}

	/* Now wipe the last record */
	rc = blocklevel_smart_write(ctx->bl, ctx->gard_data_pos + (largest * sizeof_gard(ctx)),
	                            &null_gard, sizeof(null_gard));
	printf("done\n");

	return rc;
}

static int reset_partition(struct gard_ctx *ctx)
{
	int i, rc;
	struct gard_record gard;
	memset(&gard, 0xFF, sizeof(gard));

	rc = blocklevel_smart_erase(ctx->bl, ctx->gard_data_pos, ctx->gard_data_len);
	if (rc) {
		fprintf(stderr, "Couldn't erase the gard partition. Bailing out\n");
		return rc;
	}
	for (i = 0; i + sizeof_gard(ctx) < ctx->gard_data_len; i += sizeof_gard(ctx)) {
		rc = blocklevel_write(ctx->bl, ctx->gard_data_pos + i, &gard, sizeof(gard));
		if (rc) {
			fprintf(stderr, "Couldn't reset the entire gard partition. Bailing out\n");
			return rc;
		}
	}

	return 0;
}

static int do_clear(struct gard_ctx *ctx, int argc, char **argv)
{
	int rc;
	uint32_t id;

	if (argc != 2) {
		fprintf(stderr, "%s option requires a GARD record or 'all'\n", argv[0]);
		return -1;
	}

	if (strncmp(argv[1], "all", strlen("all")) == 0) {
		printf("Clearing the entire gard partition...");
		fflush(stdout);
		rc = reset_partition(ctx);
		printf("done\n");
	} else {
		id = strtoul(argv[1], NULL, 16);
		rc = do_iterate(ctx, do_clear_i, &id);
	}

	return rc;
}

int check_gard_partition(struct gard_ctx *ctx)
{
	int rc;
	struct gard_record gard;
	char msg[2];

	if (ctx->gard_data_len == 0 || ctx->gard_data_len % sizeof(struct gard_record) != 0)
		/* Just warn for now */
		fprintf(stderr, "The %s partition doesn't appear to be an exact multiple of"
				"gard records in size: %zd vs %u (or partition is zero in length)\n",
				FLASH_GARD_PART, sizeof(struct gard_record), ctx->gard_data_len);

	/*
	 * Attempt to read the first record, nothing can really operate if the
	 * first record is dead. There (currently) isn't a way to validate more
	 * than ECC correctness.
	 */
	rc = blocklevel_read(ctx->bl, ctx->gard_data_pos, &gard, sizeof(gard));
	if (rc == FLASH_ERR_ECC_INVALID) {
		fprintf(stderr, "The data at the GUARD partition does not appear to be valid gard data\n");
		fprintf(stderr, "Clear the entire GUARD partition? [y/N]\n");
		if (fgets(msg, sizeof(msg), stdin) == NULL) {
			fprintf(stderr, "Couldn't read from standard input\n");
			return -1;
		}
		if (msg[0] == 'y') {
			rc = reset_partition(ctx);
			if (rc) {
				fprintf(stderr, "Couldn't reset the GUARD partition. Bailing out\n");
				return rc;
			}
		}
		/*
		 * else leave rc as is so that the main bails out, not going to be
		 * able to do sensible anyway
		 */
	}
	return rc;
}

__attribute__ ((unused))
static int do_nop(struct gard_ctx *ctx, int argc, char **argv)
{
	fprintf(stderr, "Unimplemented action '%s'\n", argv[0]);
	return EXIT_SUCCESS;
}

struct {
	const char	*name;
	const char	*desc;
	int		(*fn)(struct gard_ctx *, int, char **);
} actions[] = {
	{ "list", "List current GARD records", do_list },
	{ "show", "Show details of a GARD record", do_show },
	{ "clear", "Clear GARD records", do_clear },
};

static void print_version(void)
{
	printf("Open-Power GARD tool %s\n", version);
}

static void usage(const char *progname)
{
	unsigned int i;

	print_version();
	fprintf(stderr, "Usage: %s [-a -e -f <file> -p] <command> [<args>]\n\n",
			progname);
	fprintf(stderr, "-e --ecc\n\tForce reading/writing with ECC bytes.\n\n");
	fprintf(stderr, "-f --file <file>\n\tDon't search for MTD device,"
	                " read from <file>.\n\n");
	fprintf(stderr, "-p --part\n\tUsed in conjunction with -f to specify"
	                " that just\n");
	fprintf(stderr, "\tthe GUARD partition is in <file> and libffs\n");
	fprintf(stderr, "\tshouldn't be used.\n\n");


	fprintf(stderr, "Where <command> is one of:\n\n");

	for (i = 0; i < ARRAY_SIZE(actions); i++) {
		fprintf(stderr,  "\t%-7s\t%s\n",
				actions[i].name, actions[i].desc);
	}
}

static struct option global_options[] = {
	{ "file", required_argument, 0, 'f' },
	{ "part", no_argument, 0, 'p' },
	{ "ecc", no_argument, 0, 'e' },
	{ 0 },
};
static const char *global_optstring = "+ef:p";

int main(int argc, char **argv)
{
	const char *action, *progname;
	char *filename = NULL;
	struct gard_ctx _ctx, *ctx;
	uint64_t bl_size;
	int rc, i = 0;
	bool part = 0;
	bool ecc = 0;

	progname = argv[0];

	ctx = &_ctx;
	memset(ctx, 0, sizeof(*ctx));

	/* process global options */
	for (;;) {
		int c;

		c = getopt_long(argc, argv, global_optstring, global_options,
				NULL);
		if (c == -1)
			break;
		switch (c) {
		case 'e':
			ecc = true;
			break;
		case 'f':
			/* If they specify -f twice */
			free(filename);

			filename = strdup(optarg);
			if (!filename) {
				fprintf(stderr, "Out of memory\n");
				return EXIT_FAILURE;
			}
			break;
		case 'p':
			part = true;
			break;
		case '?':
			usage(progname);
			rc = EXIT_FAILURE;
			goto out_free;
		}
	}

	/*
	 * It doesn't make sense to specify that we have the gard partition but
	 * read from flash
	 */
	if (part && !filename) {
		usage(progname);
		return EXIT_FAILURE;
	}

	/* do we have a command? */
	if (optind == argc) {
		usage(progname);
		rc = EXIT_FAILURE;
		goto out_free;
	}

	argc -= optind;
	argv += optind;
	action = argv[0];

	if (arch_flash_init(&(ctx->bl), filename, true)) {
		/* Can fail for a few ways, most likely couldn't open MTD device */
		fprintf(stderr, "Can't open %s\n", filename ? filename : "MTD Device. Are you root?");
		rc = EXIT_FAILURE;
		goto out_free;
	}

	rc = blocklevel_get_info(ctx->bl, NULL, &bl_size, NULL);
	if (rc)
		goto out;

	if (bl_size > UINT_MAX) {
		fprintf(stderr, "MTD device bigger than %i: size: %" PRIu64 "\n",
			UINT_MAX, bl_size);
		rc = EXIT_FAILURE;
		goto out;
	}
	ctx->f_size = bl_size;

	if (!part) {
		rc = ffs_init(0, ctx->f_size, ctx->bl, &ctx->ffs, 1);
		if (rc)
			goto out;

		rc = ffs_lookup_part(ctx->ffs, FLASH_GARD_PART, &ctx->gard_part_idx);
		if (rc)
			goto out;

		rc = ffs_part_info(ctx->ffs, ctx->gard_part_idx, NULL, &(ctx->gard_data_pos),
				&(ctx->gard_data_len), NULL, &(ctx->ecc));
		if (rc)
			goto out;
	} else {
		if (ecc) {
			rc = blocklevel_ecc_protect(ctx->bl, 0, ctx->f_size);
			if (rc)
				goto out;
		}

		ctx->ecc = ecc;
		ctx->gard_data_pos = 0;
		ctx->gard_data_len = ctx->f_size;
	}

	rc = check_gard_partition(ctx);
	if (rc) {
		fprintf(stderr, "Does not appear to be sane gard data\n");
		goto out;
	}

	for (i = 0; i < ARRAY_SIZE(actions); i++) {
		if (!strcmp(actions[i].name, action)) {
			rc = actions[i].fn(ctx, argc, argv);
			break;
		}
	}

out:
	if (ctx->ffs)
		ffs_close(ctx->ffs);

	file_exit_close(ctx->bl);

	if (i == ARRAY_SIZE(actions)) {
		fprintf(stderr, "%s: '%s' isn't a valid command\n", progname, action);
		usage(progname);
		rc = EXIT_FAILURE;
		goto out_free;
	}

	if (rc > 0) {
		show_flash_err(rc);
		if (filename && rc == FFS_ERR_BAD_MAGIC)
			fprintf(stderr, "Maybe you didn't give a full flash image file?\nDid you mean '--part'?\n");
	}

out_free:
	free(filename);
	return rc;
}